Plantanimal symbiosis

One of the hallmarks of coral reefs is the high number of mutualistic symbiotic relationships across a large range of organisms. These relationships number in the thousands and involve all sorts of interactions, from those between gobies and burrowing shrimp to the cellular symbioses between sponges and bacteria. One of the central hypotheses surrounding coral reefs is that the large proportion of mutualistic symbioses have arisen due to the low nutrient conditions that dictate the advantages...

What Are Bryozoans

Anyone seeing bryozoans for the first time might mistake them for turfing seaweeds, hydroids, or tiny corals. Bryozoans are zoologically unrelated to reef corals, of course, but their hard, calcareous crustose, mounded, and branching colonies superficially resemble those of cnidarians. Whereas in the tropics, bryozoans are mostly dwarfed by stony corals, in cooler temperate waters they come into their own, and can form bio-herms and mini-reefs. Bushy bryozoans used to be called moss animals...

Fishes The Most Diverse Vertebrates

Fish are the largest and most diverse group of vertebrates on the planet. With an estimated 32 500 species they constitute approximately half of all the known BOX 28.1 CATALOGUES AND KEY REFERENCES FOR IDENTIFICATION OF GREAT BARRIER REEF FISHES Carpenter, K. E., and Niem. V. H. (Eds) (1998). 'FAO Species Identification Guide for Fishery Purposes. The living marine resources of the Western Central Pacific. Vols 1-6.' (FAO Rome.) Eschmeyer, W. N. (Ed.) (1998). Catalog of Fishes. Center for...

Polychaetes

Polychaetes are the most diverse and abundant of the worm groups and originally were referred to as a class within the Phylum Annelida, together with the earthworms (Class Oligochaeta) and the leeches (Class Hirudinea), and this classification will be found in many textbooks. Recent studies (both morphological and molecular) on the annelids have failed to show that they are a monophyletic group, and while the earthworms and leeches do form a single clade (the clitellates) their relationship to...

Taxonomic Overview

Octocorals are sessile animals with a mobile larval phase that are only found in marine systems. Octocor-allia are a subclass within the Class Anthozoa. The distinguishing characteristic of this subclass is that their polyps always bear eight tentacles hence octo-coral , which are fringed by one or more rows of pinnules along both edges Fig. 21.1 . The popular term 'soft coral' points to the fact that most octocorals, in contrast to the related hard corals, have no massive solid skeleton....

Buoyant weight method

From the difference in density between calcium carbonate and seawater known entities , it is possible to convert the weight of an object that has been measured in sea water into an absolute measure of calcium carbonate deposition. Assumptions made in applying this technique are that the only negatively buoyant part of the coral colony is its calcium carbonate, which is largely true for the tissues of corals. This technique has the advantage of producing an accurate measurement of the total...

Mangroves Overview

Roots Avicennia Ilicifolius

Mangroves are a diverse group of predominantly tropical trees and shrubs growing in the upper half of the intertidal zone of coastal areas worldwide. They are well known for their morphological and physiological adaptations for life coping with salt, saturated soils and regular tidal inundation, notably with specialised attributes like exposed breathing roots above ground, extra stem support structures, salt-excreting leaves, low water potentials and high intracellular salt concentrations to...

Box 211 Techniques Used To Collect Preserve And Investigate Octocoral Colonies

Heliopora Coerulea Close

When taxonomic identification is attempted, a photograph showing the entire colony and its growth form is advantageous, and close-ups of details of the surface and polyp structures are useful for reference. Although with practice it is possible to identify a number of octocorals to genus level underwater or from photographs, it is rare that they can be identified to species level because a compound microscope is needed to investigate sclerites in detail. Most soft corals have different...

Brodie and K Fabricius

Connell Catchment Whitsundays

The Great Barrier Reef GBR region with its two layers of protected areas the GBR Marine Park and the GBR World Heritage Area is a large marine ecosystem adjacent to the north-east Australian coast. The land adjacent to the GBR forms the GBR Catchment Area GBRCA Fig. 11.1 from which many rivers and streams discharge into the GBR. As the GBRCA has been developed for agricultural, industrial and residential use over the last 150 years, waters discharged from GBRCA rivers have contained increasing...

Body Plan

Swains Reef Fishing

There is no standard molluscan shape and, indeed, there is no word in the English language that takes in the whole of the Phylum Mollusca. The term 'mollusc' means soft-bodied and all molluscs lack an internal supporting skeleton, therefore, in its absence, there is no 'typical' shape that is characteristic for the phylum and the shapes of molluscan animals are very variable. In fact, the shape of the molluscan animal is largely determined by the shape of the external shell it manufactures for...

Size Hierarchy Of Organisms

Mochromatose Photos

Plankton ranges in size from a few microns to metres. An understanding of planktonic assemblages, therefore, is based on a synthesis from equipment that is suited to collecting specific size fractions of plankton. Traditionally, plankton has been broken into femtoplankton lt 0.2 m the viruses picoplankton 0.2-2 m including bacteria, cyanobacteria and prochlorophytes that are primary producers, heterotrophs and nitrogen fixers Fig. 14.6 nanoplankton 2-20 m flagellates, diatoms and cyanobacteria...

Plankton And Climate Change

It is well known that physical forcing, through changes in climatic conditions, has a great influence on planktonic assemblages. Phytoplankton has a major role in the recycling of global CO2. For this reason, anything deleterious that happens to phytoplankton will have a cascade effect through the entire food chain. Pelagic ecosystems are well known for trophic cascades and it is generally assumed that nutrient supply and subsequent growth of phytoplankton will result in 'bottom-up' control of...

Diversity Of Great Barrier Reef Macroalgae

Peyssonnelia

Taxonomic diversity and classification Macroalgae are taxonomically classified into four different Phyla Rhodophyta from the Greek 'rhodon' meaning 'red rose' and 'phyton' meaning 'plant' red algae , Ochrophyta Class Phaeophyceae, from the Greek 'phaios' meaning 'brown' brown algae , Chloro-phyta from the Greek 'chloros' meaning 'green' green algae and Cyanobacteria from the Greek 'cyanos' meaning 'dark blue' blue-green algae Table 15.1 . This systematic classification is based on the...

Box 202 Families And Genera Of Scleractinia Hard Corals On The Great Barrier Reef

Coscinaria

Families 1 to 6 are dominant in the ecology of the GBR. Genera and families in bold are suggested as a first learning tool for the beginner. Genera in bold here are illustrated in this chapter. Asterisked genera are azooxanthellate. 7 Family Astrocoeniidae Stylocoeniella 4 Family Pocilloporidae Pocillopora Australia, and exhibit a number of different strategies in the way they release their gametes for example, gametes may be negatively rather than positively buoyant in some species. The genera...

Order Actiniaria Sea Anemones

Throughout the world, sea anemones occur in most marine environments, from rocky and soft intertidal to deep abyssal substrata, and in many sizes from more than a metre in diameter down to a millimetre or two. Large sea anemones can be seen in both tropical reefs and deep Antarctic waters, but the families represented differ, with many of the deep sea species having strong gelatinous column walls or heavy external coatings and very large mouths while tropical species tend to have soft bodies,...

Js ipf w

Coral Tubular

Figure 21.17 Briareum sp. family Briareidae . A, colony B, some of the sclerites representative of this genus. Photo K. Fabricius illustration P. Alderslade. Annella Fig. 21.18 . Members of this genus are large reticulate fans up to 2 m in diameter. The axial skeleton is comprised of gorgonin and partially fused, smooth, sinuous sclerites. Sclerites of the cortex are double discs and spindles. Colour brown, orange, red or yellow. Uncommon. Similar genera Echinogorgia and Verrucella. Family...

P A Hutchings M J Kingsford O Hoegh Guldberg

The Great Barrier Reef is one of the world's most spectacular natural features and one of the few biological structures visible from space Fig. 1.1 . The sheer size of the GBR Marine Park over 360 000 km2 as well its beauty and biodiversity draw people from all over the world. The reef stretches over 2200 km from subtropical waters 27 S to the tropical waters of Torres Strait 8 S and as far as 400 km from the coast to the outer shelf slope. For Australians, the reef is a source of much pride...

Box 171 Chemical Defence

Phosphorus Symbiont Sponge

Sponges are among the most toxic of animals, with toxins derived from one or a combination of the sponge's own metabolic products, sequestered chemicals excreted by other reef organisms and filtered by sponges, and symbioses with a variety of microbial in-floras. These toxins are thought to have a variety of biological functionality including repelling predators, out-competing other sessile reef organisms for space, controlling parasites and microbes, chemical recognition between host and...